README

This package comprises of 2 main classes, Image and ImageFilter which has 8 filter sub-classes that it can use to apply a desired filter to your image. Image depends on the GD php extension to be loaded on your server. More information on GD can be found at: http://php.net/manual/en/book.image.php

Manipulating images in raw PHP using the GD image* functions requires a lot of boilerplate code. The intent of this package is to handle those requirements and make it simple for developers to accomplish those tasks through easy to use (and remember) methods.

All classes in this package are supported by the auto-loader so can be invoked at any time.

Construction

When creating a new Image object, the constructor will check that the gd extension is loaded, and throw a RuntimeException if it is not.

The constructor takes a single optional $source parameter. This argument can be one of two things:

A variable containing an existing, valid image resource created using a imagecreate* method.

A string containing a valid, absolute path to an image

If you choose the first option, the class sets the protected property $handle to the provided image resource.
If you choose the second option, the class will call the loadFile method, passing along the $source parameter.

useJoomla\Image\Image;// Creating a new Image object, passing it an existing handle.$resource=imagecreate(100, 100);$image=newImage($resource);// Creating a new Image object, passing it an image path$image=newImage(JPATH_ROOT.'/media/com_foo/images/uploads/bar.png');// Creating a new Image object then manually calling `loadFile`$image=newImage;$image->loadFile(JPATH_ROOT.'/media/com_foo/images/uploads/bar.png');

Usage

Keep in mind that most public methods return a Image instance with a valid image handle for easy method chaining. The examples for each method will break each method call out to be able to comment on what the code is doing, but production code can be chained like so (if you prefer):

Since Platform version 12.3, there is a new destroy() method that gets called in appropriate places throughout the class which runs the imagedestroy function to free memory associated with an image handle. This method is called before each time an image handle is replaced (when $createNew is set to false) as well as in the class __descruct method as a final cleanup.

The resize method

Accepted Parameters

$width: The width of the resized image in pixels or a percentage.

$height: The height of the resized image in pixels or a percentage.

$createNew: If true the current image will be cloned, resized and returned; else the current image will be resized and returned.

In this example, we use the createThumbs method of Image. This method takes 2 parameters. The first parameter can be a string containing a single size in WIDTHxHEIGHT format, or it can be an array of sizes in the format (as shown in the example). The second parameter specifies the resize method. (See Resize Methods below)

To receive Image instances without saving them to disk, use generateThumbs method with arguments $thumbSizes and $creationMethod.

Resize Methods

The resize, createThumbs and generateThumbs methods take an optional parameter that defines what method to use when scaling an image.
This parameter can be one of the following:

Image::SCALE_FILL - Gives you a thumbnail of the exact size, stretched or squished to fit the parameters.

Image::SCALE_INSIDE - Fits your thumbnail within your given parameters. It will not be any taller or wider than the size passed, whichever is larger.

Image::SCALE_OUTSIDE - Fits your thumbnail to the given parameters. It will be as tall or as wide as the size passed, whichever is smaller.

Image::SCALE_FIT - Fits your thumbnail to given boundaries maintaining aspect ratio. Result will be aligned vertically to center and horizontally to middle.

Image::CROP - Gives you a thumbnail of the exact size, cropped from the center of the full sized image.

Image::CROP_RESIZE - As above, but gives a clean resize and crop from center.

The toFile method

Accepted Parameters

$path: The filesystem path to save the image.
When null, the raw image stream will be outputted directly.

$type: The image type to save the file as (IMAGETYPE_GIF|IMAGETYPE_PNG|IMAGETYPE_JPEG).

$options: The image type options to use in saving the file.
Use quality key to set compression level (0..9 for PNGs and 0..100 for JPEGs)

Example: Using Image::toFile() to save the image as JPEG with 65 compression level